Method and Apparatus for Inserting an Implant in the Cornea of the Eye

ABSTRACT

Methods, devices, and systems for inserting an implant in the cornea ( 105 ) of the eye, where the implant is a microshunt device ( 405, 515 ). The microshunt device may comprise an inlet ( 425 ) section comprising at least one lumen and at least one inlet opening; an outlet ( 420 ) section comprising at least one lumen that connects to at least one outlet opening; and where the microshunt device ( 405, 515 ) is configured to be implanted within the cornea ( 105 ) of an eye, where the microshunt device effects the flow of aqueous humor from an anterior chamber ( 160, 235 ) of the eye to the anterior surface of the cornea ( 410, 630 ), bypassing the trabecular meshwork ( 145, 240 ), thereby diverting aqueous humor from the anterior chamber ( 160, 235 ) to the surface of the cornea ( 410, 630 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of Provisional PatentApplication No. 62/133,955 filed Mar. 16, 2015 and is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The invention, in its several embodiments, pertains to medical devicesfor control of glaucoma and/or dry eye, and more particularly to amethod and apparatus for inserting a glaucoma implant in the cornea ofthe eye.

BACKGROUND

Glaucoma is a term describing a group of eye disorders caused when theintraocular pressure within the eye increases, thereby causing retinaland optic nerve damage and subsequent loss of vision. The anteriorchamber is the cavity located between the cornea and the lens, and isfilled with a fluid (i.e., aqueous). Aqueous fluid is continuouslyproduced by secretions from the ciliary body. The aqueous drains fromthe anterior chamber through the drainage angle and into the venoussystem. In a normal situation, aqueous production is equal to aqueousoutflow through the drainage angle (angle), and intraocular pressureremains fairly constant in a range considered to be safe, for example,15 to 21 mmHg range. Glaucoma occurs when aqueous does not drainsufficiently from the anterior chamber through the angle, causing anincrease in intraocular pressure above the safe range. Raisedintraocular pressure (generally above 21 mm Hg in humans and above 28 mmHg in cats, dogs, and horses) is the most important and currently theonly modifiable risk factor for treating glaucoma. Lowering thisintraocular pressure is the major treatment goal in all glaucomapatients.

In the human eye, aqueous drains from the anterior chamber through thetrabecular meshwork into a collecting channel, called Schlemm's canal.From Schlemm's canal, aqueous flows into collector channels that joinSchlemm's canal, and then into the episcleral venous system. However,the anatomy of the canine, feline, and equine iridocorneal drainageangle has significant differences compared with the human eye. Theseeyes have pillars of tissue (pectinate ligaments) as the most anteriorpart of the iridocorneal angle, which communicate with a wide region(the ciliary cleft) that drains aqueous into the uveal and corneoscleraltrabecular meshwork. From there, aqueous enters into one or moredrainage veins that comprise the angular aqueous plexus (AAP), and thenexits the eye via episcleral veins.

In all species, glaucoma can be roughly divided into two maincategories, “open-angle” (or OAG) and “closed angle” or “angle-closure”(or ACG) glaucoma. In open-angle glaucoma, the anterior chamber remainsopen, but the exit of aqueous through the trabecular meshwork isreduced. Closed-angle glaucoma is caused by closure of the angle,preventing drainage of aqueous out of the anterior chamber.

Glaucoma can also be classified as “primary” (inherited) and “secondary”(non-inherited). Secondary glaucoma can be caused by injury, abnormalstructures, inflammation, tumors, certain drugs, or diseases. Bothprimary and secondary glaucoma can be open or closed angle.

Despite its importance, the long-term control of human and veterinaryglaucoma continues to be a challenge and is often unsuccessful incontrolling the glaucoma and/or maintaining vision. Current treatmentsfor glaucoma include medications and/or surgery to decrease intraocularfluid production, increase fluid drainage from the eye, or both.

In both human and veterinary medicine, few advancements have been madein medical and surgical therapy for glaucoma. Medical and surgicaltreatment is expensive and unaffordable to a large majority of human andveterinary glaucoma patients. Medications can cause side effects and arefrequently ineffective in long-term control of glaucoma. When drugtherapy fails, surgical therapy is needed.

Various forms of surgery to treat glaucoma include methods to open thefluid drainage channels, reduce fluid production by the ciliary body, orboth. Multiple surgeries may be required, and frequently medications arealso needed to help control intraocular pressure postoperatively.

In humans, there are many different surgical procedures for control ofopen-angle glaucoma. These surgeries involve procedures thatmechanically disrupt the trabecular meshwork, improve outflow of aqueousthrough the drainage angle, making holes in the peripheral iris,filtering procedures (penetrating or non-penetrating), tube shunts(valved or non-valved), reduce aqueous fluid production, or involvemanipulations of Schlemm's canal These surgeries are all majoroperations that are designed for treatment of open-angle glaucoma, Mostof these surgical techniques are not applicable for the canine, feline,or equine eye because of the lack of Schlemm's canal in these species,because they are designed mainly for the treatment of open-angleglaucoma rather than closed-angle glaucoma.

Various tube-shunt drainage devices have been developed for treatment ofclosed-angle glaucoma and divert aqueous fluid out of the eye to thesubconjunctival space (Ahmed valve, Molteno glaucoma shunt) or into thefrontal sinus or nasal cavity (Cullen shunt) Shunt surgeries eventuallyfail due to clogging of the drainage tube, and/or due to formation of afibrous tissue capsule over the shunt, causing decreased flow of aqueousfluid out of the eye. This causes return of glaucoma and necessitatesfurther treatment.

All of the above surgeries have numerous disadvantages including poorlong-term prognosis for control of glaucoma. They need to be performedin an operating room, involve substantial trauma to the eye, requiregreat surgical skill, have the potential for significant complications,are expensive, and have limited to no availability for many pet owners.Most significantly, the anatomy of the canine, feline, and equineiridocorneal filtration angle has significant differences compared withthe human eye, which renders most human glaucoma-management surgeriesineffective in dogs, cats, and/or horses

Acute angle-closure glaucoma in dogs is an emergency and requires thatthe intraocular pressure be reduced to a safe range within minutes orhours. Glaucoma surgeries which attempt to preserve vision are oftendeclined by clients because they may need to travel long distances tofind a veterinary ophthalmologist that can provide such surgeries, thecost of surgery is very expensive, pre-and post-surgical treatments aretime-consuming and expensive, and the patient may be uncooperative. Iftreatment is delayed, permanent blindness will usually occur, oftenwithin a matter of a few hours. In most dogs, glaucoma is also a verypainful condition. Once the eye is blinded by glaucoma, thenglaucoma-eliminating surgery (such as enucleation, i.e., removal, of theeye, evisceration of the eye with surgical placement of an intraocularprosthesis, or an ablation procedure) is required to restore comfort andeliminate the requirement for treatment. Therefore, new surgicalapproaches need to be developed that provide faster, better, safer, andless expensive care for both human and veterinary glaucoma patients,both in the short- and long-term.

SUMMARY

A device embodiment of the microshunt device may comprise: an inletsection comprising at least one lumen and at least one inlet opening; anoutlet section comprising at least one lumen that connects to at leastone outlet opening; and wherein the microshunt device is configured tobe implanted within a cornea of an eye, wherein the microshunt deviceeffects the flow of aqueous humor from an anterior chamber of the eye tothe anterior surface of the cornea, bypassing the trabecular meshwork,thereby diverting aqueous humor from the anterior chamber to the surfaceof the cornea; and wherein the microshunt is prevented from migratingfrom an implantation site. The microshunt device may further comprise aplurality of lumens arranged in a series and parallel to each other.Optionally, the microshunt device may be retained, before implantation,via a plunger-type deployment mechanism. Additionally, the microshuntdevice may be deployed from an applicator and once a distal section ofthe applicator passes beyond a corneal endothelium and into the anteriorchamber.

In another embodiment, the microshunt deployment may be facilitated bythe plunger-type deployment mechanism with an associated deploymentactuator mounted on a handle of the applicator. Optionally, themicroshunt device may utilizes fluid flow from a higher pressureenvironment to a lower pressure environment. In one embodiment, themicroshunt device may further comprise a flow-restricting member withinthe lumen that may be configured to: control globe decompression afterthe microshunt is implanted; and control flow of the aqueous humor outof the eye. Additionally, the flow-restricting member within the lumenmay act to partially fill the lumen; and the flow-restricting memberwithin the lumen may be a wire having a diameter thickness smaller thanthe lumen. In some embodiments, the flow-restricting member may befurther configured to control the flow of aqueous humor based onthickness of diameter.

A system embodiment may comprise: a barrel holder, wherein the holdermay have a proximal end and a distal end, wherein the proximal end ofthe holder contains a plunger and the distal end contains an extrusiontip; wherein the extrusion tip further comprises a first lumen and atleast one irrigating hole disposed between the proximal and distal endsof the extrusion tip; wherein the irrigating hole is in fluidcommunication with the lumen; a microshunt device, wherein themicroshunt device is configured to be implanted within a cornea of aneye, and wherein the microshunt effects the flow of aqueous humor froman anterior chamber of the eye to the anterior surface of the cornea,bypassing the trabecular meshwork; and a barrel holder comprising asecond lumen, wherein a distal end of the second lumen opens to thedistal end of the extrusion tip portion; and wherein the holder isconfigured to hold the microshunt device during implantation of themicroshunt device within the eye, and the holder releases the microshuntdevice upon deployment of the microshunt device.

Optionally, the proximal end of the second lumen may be separated fromthe first lumen of the extrusion tip. Additionally, fluid may be infusedthrough a lumen of the microshunt into the anterior chamber. In onesystem embodiment, the system may further comprise a flow-restrictingmember configured to: control globe decompression after the microshuntis implanted; and control flow of aqueous out of the eye.

A method embodiment may comprise the steps of: providing a microshuntfor diverting aqueous humor from the anterior chamber of a cornea to thesurface of the cornea; providing an applicator for delivering themicroshunt into the cornea; creating an incision in and through thecornea for the microshunt placement via a distal portion of theapplicator comprising a cutting tool; placing tightly, the microshuntwithin the cannula lumen of the applicator, wherein the microshunt isretained by a plunger-type deployment mechanism; deploying themicroshunt, from the applicator, once the distal section passes beyondthe corneal endothelium and into the anterior chamber; and regulatingthe flow of the aqueous humor via the deployed microshunt onceimplanted, thereby the aqueous humor flows controllably from an anteriorchamber of the eye to the anterior surface of the cornea, bypassing thetrabecular meshwork. Optionally, securing the microshunt may be via afastening mechanism.

The regulating of the flow of the aqueous humor via the deployedmicroshunt may further comprise employing a flow-restricting member. Inone embodiment, the regulating of the flow of the aqueous humor via thedeployed microshunt may further comprise: controlling globedecompression after the microshunt is deployed and implanted via theflow-restricting member. Additionally, the flow-restricting member maybe a wire having a diameter thickness that is less than diameterthickness of the microshunt.

BRIEF DESCRIPTION OF DRAWINGS

The components in the figures are not necessarily to scale, emphasisinstead being placed upon illustrating the principals of the invention.Like reference numerals designate corresponding parts throughout thedifferent views. Embodiments are illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a mammalian eye;

FIG. 2 is a close-up view showing the relative anatomical locations ofthe trabecular meshwork, the anterior chamber, and the cornea;

FIG. 3 is a cross-sectional view of the non-primate mammalian drainageangle;

FIGS. 4A-F show a detailed external view of various embodiments of amicroshunt;

FIG. 5 shows an embodiment of an applicator for delivering a microshuntinto the cornea;

FIG. 6A depicts a front view of a method by which the microshunt isimplanted within the cornea;

FIG. 6B depicts a side view of a method by which the microshunt isimplanted within the cornea; and

FIG. 6C depicts a side view of a method by which the microshunt isimplanted within the cornea.

DETAILED DESCRIPTION

To overcome the difficulties outlined above, the present applicationdiscloses a microshunt device and method of treatment for glaucoma thatdiverts aqueous humor from the anterior chamber to the surface of thecornea. The exterior surface of the cornea is a readily-accessible sitefor long-term extraocular diversion of aqueous fluid from within the eyefor the purpose of controlling glaucoma. Additionally, the presentapplication provides for a microshunt to be implanted into the cornea sothat aqueous fluid may be drained from the anterior chamber to thesurface of the cornea, via the microshunt, such that the microshunt isprevented from migrating from its implantation site, for example, with asilver anti-microbial core, and an optional temporary flow-restrictingmember designed to (a) control globe decompression after the microshuntis implanted; (b) control flow of aqueous out of the eye; and (c) in theevent of microshunt plugging, may be used to restore microshunt patency.

Some embodiments of the apparatus for inserting a glaucoma implant inthe cornea of the eye may include devices and methods for treatment ofintraocular pressure due to glaucoma. A hollow microshunt may be adaptedfor implantation within the cornea of an eye such that aqueous humorflows controllably from an anterior chamber of the eye to the anteriorsurface of the cornea, bypassing the trabecular meshwork. In oneembodiment, the microshunt may comprise a quantity of antimicrobialpharmaceuticals to reduce the possibility of corneal and/or intraocularinfection.

A corneal implant device, and the method and apparatus for inserting themicroshunt implant into the cornea of the eye is disclosed herein. Thecorneal implant may include a small hole, cavity, orifice, or group oforifices that allow leakage of fluid from the eye onto the surface ofthe cornea. The rate of leakage of fluid from the eye may be intended,by design of the implant, to match the normal production of fluid by theeye such that pressure buildup associated with glaucoma is controlled toan acceptable pressure level. One embodiment of the corneal implant maycomprise a wire or partial plug element that is coaxially located withinthe implant device. The wire or plug element may be one of many possiblematerials including silver metal. Another embodiment of the cornealimplant may allow the adjustment of leakage rate by removing the coaxialelement and substitution of either a smaller or larger element;

where the diameter of the element may affect the size of the orifice andthereby the fluid flow. The implant may also be designed to allow fluidsof all types to be injected through the corneal implant into theinterior of the eye. Accordingly, the implant may facilitate the flow offluid on both directions, i.e., in and out of the eye.

One embodiment of the apparatus for inserting a glaucoma implant in thecornea of the eye provides a microshunt that is implantable within acornea. The microshunt may comprise an inlet section comprising at leastone lumen and one inlet opening, an outlet section having at least onelumen that connects to at least one outlet opening, where the lumen isan inside space of a tubular structure. In one embodiment, themicroshunt may further comprise a flow-restricting member within thelumen that is configured to permit fluid entering the lumen of the inletsection to pass through the flow-restricting member, enter the lumen ofthe middle section, pass into the lumen of the outlet section, and thenexit the outlet section.

Other embodiments of the apparatus for inserting a glaucoma implant inthe cornea of the eye, may provide an apparatus for implanting amicroshunt within a cornea such that the implant is placed through thecornea to drain aqueous from the anterior chamber to the surface of thecornea. The apparatus may comprise a syringe portion and a cannulaportion that has proximal and distal ends. The proximal end of thecannula portion is attached to the syringe portion. The cannula portionfurther comprises a first lumen and at least one irrigating holedisposed between the proximal and distal ends of the cannula portion.The irrigating hole is in fluid communication with the lumen. Theapparatus further includes a holder including a second lumen for holdingthe microshunt. A distal end of the second lumen opens to the distal endof the cannula portion, and a proximal end of the second lumen may beseparated from the first lumen of the cannula portion. The holder mayfunction to hold the microshunt during implantation of the device withinthe eye, and the holder releases the microshunt when a practitioneractivates deployment of the device. In some embodiments fluid is infusedthrough a lumen of the microshunt into the anterior chamber

In one embodiment, the apparatus for inserting a glaucoma implant in thecornea of the eye may be arranged where the fluid is at least one of asalt solution or viscoelastic.

Optionally, the fluid may comprise a therapeutic substance such as apharmaceutical, a gene, a growth factor, and/or an enzyme. In otherembodiments, the fluid may comprise a therapeutic substance such as anantiglaucoma drug, a beta-adrenergic antagonist, a TGF-beta compound,and/or an antibiotic. In yet other embodiments, the infusing lumen ofthe microshunt device may further comprise coupling the inflow portionof the microshunt with a fluid delivery element that transmits the fluidto the microshunt. Optionally, the apparatus for inserting a glaucomaimplant in the cornea of the eye may be so that the coupling comprisessecuring a screw thread arrangement of the fluid delivery element with areceiving thread arrangement of the microshunt.

The present application may generally relate to medical devices andmethod for continuously decompressing elevated intraocular pressure ineyes affected by glaucoma and/or for treatment of dry eye by divertingaqueous humor from the anterior chamber of the animal eye onto thesurface of the cornea through a surgically implanted shunt. The shuntdevices may provide uni-directional or bi-directional flow of fluidthrough the cornea. The shunt may include a silver-lined hollow tubeand/or a silver-impregnated antimicrobial material, having a lengthsufficient to span the distance between the corneal endothelial surfaceand the outside of the cornea, and a seal device to anchor the shuntdevice within the cornea. In some embodiments, the shunt may alsoinclude a fluid pressure openable valve or a sphincter valve in thetube, allowing for controlled flow of aqueous humor from the anteriorchamber through the tube on to the corneal surface when implanted.

In one embodiment, the apparatus may include a handpiece device toimplant the microshunt; where the handpiece may have a distal end and aproximal end; a (sharp) tip connected to the distal end of thehandpiece, the sharp tip having a distal portion and being configured toperform a corneal incision and into the anterior chamber of the eye; aholder attached to the distal portion of the elongate tip, the holderconfigured to hold and release the microshunt; and an actuator on thehandpiece that actuates the holder to release the microshunt from theholder into the cornea.

Embodiments of the present application further describe surgical andtherapeutic treatment of glaucoma through reduction of intraocularpressure via the use of the microshunt. While the description sets forthvarious embodiment specific details, the description is illustrativeonly and should not be construed in any way as limiting the invention.Furthermore, various applications of the invention, and modificationsthereto, which may occur to those who are skilled in the art, are alsoencompassed by the general concepts described below.

FIG. 1 is a cross-sectional view of a mammalian eye, while FIG. 2 is aclose-up view showing the relative anatomical locations of thetrabecular meshwork (145), the anterior chamber (160), and the cornea(105). The sclera (120) is a thick collagenous tissue that covers theentire eye except a portion that is covered by the cornea (105). Thecornea (105) is a thin transparent tissue that focuses and transmitslight into the eye and through the pupil (155), which is a circular holein the center of the iris (115) (colored portion of the eye). The cornea(105) merges into the sclera (120) at a juncture referred to as thelimbus (110). The ciliary body (140) extends along the interior of thesclera and is coextensive with the choroid (130). The choroid (130) is avascular layer of the eye, located between the sclera (120) and theretina (125). The optic nerve (135) transmits visual information to thebrain and is the anatomic structure that is progressively damaged byglaucoma.

FIG. 2 is a cross-sectional view of a primate drainage angle; as shownin FIGS. 2 and 3, the anatomy of the drainage angle of the primate eye(FIG. 2) is considerably different from the anatomy of the drainageangle of the non-primate mammalian eye (FIG. 3). The anterior chamber(235) of the eye, which is bound anteriorly by the cornea (230) andposteriorly by the iris (245) and the lens (250), is filled with aqueoushumor (hereinafter referred to as “aqueous”). Aqueous is produced by theciliary body (255), then moves anteriorly through the pupil (260) andreaches the anterior chamber angle, formed between the iris and thecornea. In a normal eye, aqueous is removed from the anterior chamberthrough the trabecular meshwork (240). Aqueous passes through thetrabecular meshwork into Schlemm's canal (225) and thereafter through aplurality of aqueous collector veins (220), which merge with episcleralblood-carrying veins (210), and into systemic venous circulation.Intraocular pressure is maintained by an intricate balance betweensecretion and outflow of aqueous in the manner described above. Glaucomais, in most cases and as described previously, characterized by anexcessive buildup of aqueous in the anterior chamber, which leads to anincrease in intraocular pressure. Fluids are relatively incompressible,and thus intraocular pressure is distributed uniformly throughout theeye.

Traditional procedures that create a hole or opening for implanting adevice through the tissues of the conjunctiva (215) and sclera (205), orinserting a microshunt through trabecular meshwork (240) having a distalportion disposed within Schlemm's canal (225) and a proximal portiondisposed within the anterior chamber of the eye (235), involve extensivesurgery, as compared to surgery for implanting a device, as describedherein, which ultimately resides entirely within the confines of thecornea (230).

FIG. 3 is a cross-sectional view of the non-primate mammalian drainageangle. The anterior chamber (325) of the eye, which is bound anteriorlyby the cornea (320) and posteriorly by the iris (330) and the lens(335), is filled with aqueous humor (hereinafter referred to as“aqueous”). Aqueous is produced by the ciliary body (305), then movesanteriorly through the pupil (360) and reaches the anterior chamberangle, formed between the iris and the cornea. Aqueous drains betweenpillars of tissue (pectinate ligaments) (345) as the most anterior partof the iridocorneal angle, which communicate with a wide region (theciliary cleft) (340) that drains aqueous into the uveal andcorneoscleral trabecular meshwork. From there, aqueous enters into oneor more drainage veins that comprise the angular aqueous plexus (AAP)(355), and then exits the eye via the intrascleral venous plexus (350)which drain into episcleral veins between the sclera (310) and theconjunctiva (315). Note the absence of a Schlemm's canal in thenon-primate mammalian drainage angle.

FIG. 4A depicts an embodiment of a hollow microshunt (405) that may beused in order to facilitate/effect the outflow of aqueous from theanterior chamber through the cornea onto the surface of the cornea(410), and so that the intraocular pressure is reduced. In across-section of the illustrated embodiment, the microshunt comprises aninlet section, having an inlet opening (425), a middle section (415),and an outlet section (420) having at least one opening. The middlesection (415) may be an extension of, or may be coextensive with, theinlet section. The device comprises at least one lumen within section,which is in fluid communication with the inlet opening and the outletopening thereby facilitating transfer of aqueous through the device.

The lumen and the remaining body of the outlet section may have across-sectional shape that is oval, circular, or other appropriateshape. In one embodiment, the middle section may have a length that isroughly slightly larger than the thickness of the cornea, whichtypically ranges between about 400 μm and about 800 μm.

To further stent, shunt, or open the outflow pathway after implantingthe microshunt, a plurality of elevated, that is, protruding axially,supports or pillars may be located at the distal-most end of the outletsection sized and configured for allowing media, for example, aqueous,liquid, balanced salt solution, viscoelastic fluid, therapeutic agents,or the like, to be transported freely.

The microshunt may further comprise a flow-restricting member, which istightly retained within a lumen. The flow-restricting member is sizedand configured for maintaining a safe (normal) intraocular pressure ofthe fluid within the anterior chamber for a suitable period of time.Alternatively, the flow-restricting member may be situated in anylocation within the device such that fluid flow is restricted such thatintraocular pressure is maintained at a safe level within the anteriorchamber. The flow-restricting member may, in other embodiments, be afilter made of a material selected from, but not limited to, thefollowing filter materials: expanded polytetrafluoroethylene, cellulose,ceramic, glass, Nylon, plastic, and fluorinated material such aspolyvinylidene fluoride (“PVDF”).

The microshunt allows leakage from the higher pressure environment,i.e., eye interior, to the lower pressure environment, i.e., eyeexterior. The microshunt device may incorporate a small orifice orseries of orifices arranged either in series or parallel or acombination thereof. The calculated effective orifice size may have a0.001 inch diameter. An exemplary method to control the fluid flow maybe one in which a small effective diameter hole may be created bypartially filling an initial hole or orifice with a plug element. Theplug element may, for example, comprise a fine diameter wire where thediameter of the wire is less than the diameter of the initial hole ororifice. A plug may also allow the microshunt performance to befine-tuned prior to surgical implantation or allow a microshunt assemblyto be tuned after surgery. In one embodiment, the effective orifice mayeven be a fused filter material. Optionally, a tool may be designed thatmay hold the microshunt body and allow a plug element to be removed andreplaced with a different plug element having a different diameter, forexample, that might be smaller or larger than the original plug.

The microshunt may be made by, for example, molding, thermo-forming,sintering, or other micro-machining techniques. The microshunt maycomprise a biocompatible material such that inflammation arising due toirritation between the outer surface of the device and the surroundingtissue is minimized. Biocompatible materials which may be used for thedevice may include, but are not limited to, titanium, stainless steel,medical grade silicone, e.g., Silastic™, available from Dow CorningCorporation of Midland, Mich.; and polyurethane, e.g., Pellethane™, alsoavailable from Dow Corning Corporation. In other embodiments, the devicemay comprise other types of biocompatible material, such as, by way ofexample, polyvinyl alcohol, polyvinyl pyrolidone, collagen, heparinizedcollagen, polytetrafluoroethylene, expanded polytetrafluoroethylene,fluorinated polymer, fluorinated elastomer, flexible fused silica,polyolefin, polyester, polysilicon, and/or a mixture of theaforementioned biocompatible materials, and the like. In anotherembodiment, the microshunt may be made of a biodegradable materialselected from a group consisting of poly (lactic acid),polyethylene-vinyl acetate, poly (lactic-co-glycolic acid), poly(D,L-lactide), poly (D,L-lactide-co-trimethylene carbonate), poly(caprolactone), poly (glycolic acid), and copolymer thereof. In otherembodiments, composite biocompatible material may be used, wherein asurface material may be used in addition to one or more of theaforementioned materials. For example, such a surface material mayinclude polytetrafluoroethylene (PTFE) (such as Teflon™), polyimide,hydrogel, heparin, therapeutic drugs (such as beta-adrenergicantagonists, TGF-beta, and other anti-glaucoma drugs, or antibiotics),and similar material.

As is well known in the art, a device coated or loaded with aslow-release substance may have prolonged effects on local tissuesurrounding the device. The slow-release delivery may be designed suchthat an effective amount of substance is released over a desiredduration. “Substance,” as used herein, is defined as any therapeutic oractive drug that may stop, mitigate, slow-down or reverse undesireddisease processes.

In one embodiment, the device may be made of a biodegradable—alsoincluding bio-erodible—material admixed with a substance for substanceslow-release into ocular tissues. In another embodiment, polymer filmsmay function as substance containing release devices whereby the polymerfilms may be coupled or secured to the device. The polymer films may bedesigned to permit the controlled release of the substance at a chosenrate and for a selected duration, which may also be episodic orperiodic. Such polymer films may be synthesized such that the substanceis bound to the surface or resides within a pore in the film so that thesubstance is relatively protected from enzymatic attack. The polymerfilms may also be modified to alter their hydrophilicity, hydrophobicityand vulnerability to platelet adhesion and enzymatic attack. The devicemay be used for a direct release of pharmaceutical preparations intoocular tissues. As discussed above, the pharmaceuticals may becompounded within the device or form a coating on the device. Any knowndrug therapy for glaucoma may be utilized.

FIGS. 4B-F depict a detailed external view of the microshunt. In someaspect, the proximal section may have a bottom peripheral surface thatis perpendicular to the lumen of the microshunt. A receiving threadarrangement may be appropriately located on the peripheral surface. Thereceiving thread arrangement may be sized and configured to releasablyreceive a screw thread arrangement for coupling together, wherein thescrew thread arrangement may be disposed at the distal end of a fluiddelivery element which has a lumen for transporting the infusing fluidinto the aqueous cavity for therapeutic purposes. In one embodiment, thecoupling of the receiving thread arrangement and the screw threadarrangement effects the fluid infusion through the lumen leak-proof. Inone embodiment, the outlet side openings, each of which may be in fluidcommunication with the lumen for transmission of aqueous, may bearranged spaced apart around the circumferential periphery of the outletsection.

FIG. 5 shows an embodiment of an applicator (500) for delivering amicroshunt into the cornea, the applicator having a fixture body (505).The distal portion comprises a cutting means (525) sharp enough forcreating an incision in and through the cornea for the microshunt (515)placement. The microshunt may be tightly placed within the cannula lumen(510) of the applicator and retained by a plunger-type (520) deploymentmechanism. The microshunt is deployed from the applicator once thedistal section passes beyond the corneal endothelium and into theanterior chamber. In one aspect, the microshunt deployment may befacilitated by the plunger-type deployment mechanism with an associateddeployment actuator mounted on the handle of the applicator. Themicroshunt may be releasably coupled with a fluid restricting or fluiddelivery element at any convenient time during the procedure. In oneaspect, the screw-unscrew coupling steps between the microshunt and thefluid delivery element may be carried out by suitably rotating the fluidrestricting or fluid delivery element with reference to the microshuntreceiving thread arrangement.

In one embodiment, the microshunt device may have a length ranging fromabout 300 um to over 1000 um. Optionally, the device may have an outsidediameter ranging between about 30 μm and about 500 μm, with the lumenhaving an exemplary set of diameters ranging between about 20 μm andabout 250 μm, respectively. In addition, the device may have a pluralityof lumens to facilitate transmission of multiple flows of aqueous orinfusing fluid.

In a method embodiment for increasing aqueous outflow in the eye of apatient, to reduce intraocular pressure therein, the method may comprisethe step of bypassing the trabecular meshwork. While in use, the devicemay be placed through the cornea, through a slit or opening. Thisopening may be created by use of a laser, a knife, thermal energy(radiofrequency, ultrasound, and microwave), cryogenic energy, or anyother available surgical cutting instrument. The opening may also behorizontal or substantially horizontal, i.e., extending longitudinallyin the same direction as the circumference of the limbus (see FIG. 1).Other opening directions may also be used, depending on the set ofcircumstances. The opening may be oriented at any angle, relative to thecircumference of the limbus that is appropriate for inserting the devicethrough the cornea and into the anterior chamber.

FIGS. 6A-C generally illustrate a method by which the microshunt (645)may be implanted within the cornea. FIG. 6A depicts a front view andFIGS. 6B and 6C depict a side view. In the illustrated method, adelivery applicator is provided, which preferably comprises a syringeportion and a cannula portion, which may comprise at least one lumen influid communication with the aqueous fluid coming from the eye. A holderat the distal portion of the cannula portion for holding the device maycomprise a lumen, a sheath, a clamp, tongs, a space, and any otheravailable means for holding the device. In the method illustrated inFIG. 6B, the device may be placed into the lumen of the deliveryapplicator (640) and then advanced to a desired implantation site withinthe cornea (605). The delivery applicator may then hold the devicesecurely during delivery and may release it when the practitionerinitiates deployment actuator of the applicator. The device may beplaced against the epithelial surface of the cornea (630), and insertedthrough the corneal stroma (635) and endothelium (625) so that the lumenof the microshunt communicates with the aqueous in the anterior chamber(620).

The microshunt device may be retained by the corneal tissue. Themicroshunt device body may have a geometry that may restrict themicroshunt device from moving either into or out of the eye aftersurgical implantation. Alternately, the microshunt device body may havea roughness, radial ridges, helical ridge or similar feature that causesthe microshunt device body to remain fixed under the very slighthydrostatic pressure associated with the glaucomatous condition. Themicroshunt device may be designed to undergo a geometry change duringimplanting in order to achieve the retention due to geometry features.The cornea may be surgically cut during implantation and allow themicroshunt device geometry to be of a fixed type with the cornea healingto form the desired retention.

In one embodiment of the microshunt corneal surgery, a patient may beplaced in an appropriate position, prepped, draped, and appropriatelyanesthetized. A small incision may then be made through the cornea witha self-trephining applicator. The incision may for example have asurface length less than about 1.0 millimeter in length. Through thecorneal incision, the anterior chamber may be accessed, thereby forminga through the cornea for stent placement. After the device isappropriately implanted, the applicator may be withdrawn and the cornealmicroshunt surgery may be concluded.

In some aspect of the microshunt corneal surgery, a method may bepresented where fluid may be injected through the microshunt into theanterior chamber. In one embodiment of the microshunt device a methodfor using a removable applicator, catheter, cannula, or tubing that isplaced ab interno through the microshunt into the anterior chamber of aneye adapted for infusing therapeutic liquid into the aqueous cavity maybe used. The fluid may be a salt solution such as Balanced SaltSolution, a viscoelastic, any other suitable viscous or non-viscousliquid, or suitable liquid loaded with drug at a concentration suitablefor therapeutic purposes without causing safety concerns. A combinationof liquids may also be used. The pressure is raised at an appropriaterate of rise to an appropriate level and for an appropriate length oftime, as determined through development studies, to provide for theexpansion of the outflow structures and/or a clearing of any blockageswithin them. The procedure may be augmented with other aids to enhanceits effectiveness. These aids may include heat, vibration (sonic orultrasonic), pulsation of a pressure front, pH, drugs, etc.

The disclosed embodiments of the microshunt device may provide a methodto simplify microshunt corneal surgeries. Accordingly, the surgery maypotentially be performed on an outpatient basis under topical or localanesthesia, or with a brief general anesthesia, with improved prognosisfor retaining vision, greatly reduced morbidity and expense. The methodand device may be used for short-term or long-term control of glaucomain all species of animals, especially, dogs, cats, and horses, includinghumans.

It is contemplated that various combinations and/or sub-combinations ofthe specific features and aspects of the above embodiments may be madeand still fall within the scope of the invention. Accordingly, it shouldbe understood that various features and aspects of the disclosedembodiments may be combined with or substituted for one another in orderto form varying modes of the disclosed invention. Further it is intendedthat the scope of the present invention herein disclosed by way ofexamples should not be limited by the particular disclosed embodimentsdescribed above

What is claimed is:
 1. A microshunt device comprising: an inlet sectioncomprising at least one lumen and at least one inlet opening; an outletsection comprising at least one lumen that connects to at least oneoutlet opening; and wherein the microshunt device is configured to beimplanted within a cornea of an eye, wherein the microshunt deviceeffects the flow of aqueous humor from an anterior chamber of the eye tothe anterior surface of the cornea, bypassing the trabecular meshwork,thereby diverting aqueous humor from the anterior chamber to the surfaceof the cornea; and wherein the microshunt device is prevented frommigrating from an implantation site.
 2. The microshunt device of claim 1further comprising a plurality of lumens arranged in a series andparallel to each other.
 3. The microshunt device of claim 1 wherein themicroshunt device is retained, before implantation, via a plunger-typedeployment mechanism.
 4. The microshunt device of claim 3 wherein themicroshunt device is deployed from an applicator and once a distalsection of the applicator passes beyond a corneal endothelium and intothe anterior chamber.
 5. The microshunt device of claim 4 wherein themicroshunt device deployment is facilitated by the plunger-typedeployment mechanism with an associated deployment actuator mounted on ahandle of the applicator.
 6. The microshunt device of claim 4 whereinthe microshunt device utilizes fluid flow from a higher pressureenvironment to a lower pressure environment.
 7. The microshunt device ofclaim 1 further comprising a flow-restricting member within the lumenthat is configured to: control globe decompression after the microshuntdevice is implanted; and control flow of the aqueous humor out of theeye.
 8. The microshunt device of claim 7 wherein the flow-restrictingmember within the lumen acts to partially fill the lumen.
 9. Themicroshunt device of claim 7 wherein the flow-restricting member withinthe lumen is a wire having a diameter thickness smaller than the lumen.10. The microshunt device of claim 7 wherein the flow-restricting memberis further configured to control the flow of aqueous humor based onthickness of diameter.
 11. A system comprising: a barrel holder, whereinthe holder has a proximal end and a distal end, wherein the proximal endof the holder contains a plunger and the distal end contains anextrusion tip; wherein the extrusion tip further comprises a first lumenand at least one irrigating hole disposed between the proximal anddistal ends of the extrusion tip; wherein the irrigating hole is influid communication with the lumen; a microshunt device, wherein themicroshunt device is configured to be implanted within a cornea of aneye, and wherein the microshunt device effects the flow of aqueous humorfrom an anterior chamber of the eye to the anterior surface of thecornea, bypassing the trabecular meshwork; and a barrel holdercomprising a second lumen, wherein a distal end of the second lumenopens to the distal end of the extrusion tip portion; and wherein theholder is configured to hold the microshunt device during implantationof the microshunt device within the eye, and the holder releases themicroshunt device upon deployment of the microshunt device.
 12. Thesystem of claim 11 wherein the proximal end of the second lumen isseparated from the first lumen of the extrusion tip.
 13. The system ofclaim 11 wherein fluid is infused through a lumen of the microshuntdevice into the anterior chamber.
 14. The system of claim 11 furthercomprising a flow-restricting member configured to: control globedecompression after the microshunt device is implanted; and control flowof aqueous out of the eye.
 15. A method comprising: providing amicroshunt for diverting aqueous humor from the anterior chamber of acornea to the surface of the cornea; providing an applicator fordelivering the microshunt into the cornea; creating an incision in andthrough the cornea for the microshunt placement via a distal portion ofthe applicator comprising a cutting tool; placing tightly, themicroshunt within the cannula lumen of the applicator, wherein themicroshunt is retained by a plunger-type deployment mechanism; deployingthe microshunt, from the applicator, once the distal section passesbeyond the corneal endothelium and into the anterior chamber; andregulating the flow of the aqueous humor via the deployed microshuntonce implanted, thereby the aqueous humor flows controllably from ananterior chamber of the eye to the anterior surface of the cornea,bypassing the trabecular meshwork.
 16. The method of claim 15 furthercomprising: securing the microshunt via a fastening mechanism.
 17. Themethod of claim 15 wherein the regulating of the flow of the aqueoushumor via the deployed microshunt further comprises employing aflow-restricting member.
 18. The method of claim 17 wherein theregulating of the flow of the aqueous humor via the deployed microshuntfurther comprises: controlling globe decompression after the microshuntis deployed and implanted via the flow-restricting member.
 19. Themethod of claim 18 wherein the flow-restricting member is a wire havinga diameter thickness that is less than diameter thickness of themicroshunt.